1. Field of the Invention
The present invention pertains to a method for cleaning well casing and tubing strings to remove accumulated debris including drilling fluid, cement compositions, pipe joint compositions and other material prior to production of well fluids. A cleaning assembly including one or more resilient plugs and a spiral brush assembly is pumped or pushed down the casing or tubing during or upon completion of the cementing operation, for example.
2. Background
In conventional oil well completion operations, upon finishing the pumping down of a cement composition through the well casing or a tubing string inserted in the casing, a drilling rig is moved back over the wellhead or put back in operation to lower a tubing string on which a mechanical scraping device is disposed for cleaning the interior wall surface of the casing or the tubing string through which stimulation fluids or well production fluids will eventually flow. This cleaning operation is expensive and time consuming in that use of the drilling rig or similar equipment is required for lowering the tubing string on which the mechanical scraping mechanism is disposed. Moreover, removal from the wellbore of the debris or other material which has accumulated on the inside wall of the casing or tubing string is difficult to accomplish. Accordingly, there has been a longfelt need for a simpler method and system for cleaning well casing and similar tubing structures in wellbores to remove unwanted material from the interior of the casing before other well operations are conducted. The present invention is believed to fill such a need with an improved method and system or apparatus as described.